Difenoconazole (Ref: CGA 169374)

Difenoconazole (Ref: CGA 169374)	Last updated: 21/08/2024
(Not known by any other names)

SUMMARY

Difenoconazole is a fungicide used for disease control in many fruits, vegetables, cereals and other field crops. Although potentially a mobile molecule it is unlikely to leach due to its low aqueous solubility. It does however have potential for particle bound transport. It is slightly volatile, persistent in soil and in the aquatic environment. There are some concerns regarding its potential for bioaccumulation. Moderately toxic to humans, mammals, birds and most aquatic organisms.

Data alerts

The following alerts are based on the data in the tables below. An absence of an alert does not imply the substance has no implications for human health, biodiversity or the environment but just that we do not have the data to form a judgement.

Environmental fate	Ecotoxicity	Human health
Environmental fate High alert: Potential for particle bound transport: High	Ecotoxicity High alert: Birds chronic ecotoxicity: High; Daphnia chronic ecotoxicity: High	Human health Moderate alert: Mammals acute toxicity: Moderate; Mammals chronic toxicity: Moderate; Possible Carcinogen; Genotoxic; Reproduction/development effects

GENERAL INFORMATION

Description

A broad spectrum fungicide with a wide-ranging activity used as a spray or seed treatment

Example pests controlled

Leafspot; Ring spot; Early blight; Barley stripe; Covered smut; Damping-off; Seed rots

Example applications

Vegetables including carrots, asparagus, brassicas; Potatoes; Cereals including barley, oats, rye, wheat, triticale; Sweetcorn; Cotton; Canola; Tomato; Pome fruits

Efficacy & activity

Wheat/Mildew=Low; Wheat/Septoria tritici=Low; Wheat/Yellow rust=Low; Wheat/brown rust=Moderate

Availability status

Current

Introduction & key dates

1988 first reported; 1989, introduced France

UK regulatory status

UK COPR regulatory status

Approved

Date COPR inclusion expires

31/12/2028

UK LERAP status

Possible - check label

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

Sweden

Date EC 1107/2009 inclusion expires

15/03/2026

EU Candidate for substitution (CfS)

Yes - two 'Persistent-Bioaccumulative-Toxic' criteria

Listed in EU database

Yes

Approved for use (✓) under EC 1107/2009 in the following EU Member States

ATAustria	BEBelgium	BGBulgaria	CYCyprus	CZCzech Republic	DEGermany	DKDenmark	EEEstonia	ELGreece
✓	✓	✓	✓	✓	✓	✓	✓	✓
ESSpain	FIFinland	FRFrance	HRCroatia	HUHungary	IEIreland	ITItaly	LTLithuania	LULuxembourg
✓	✓	✓	✓	✓	✓		✓	✓
LVLatvia	MTMalta	NLNetherlands	PLPoland	PTPortugal	RORomania	SESweden	SISlovenia	SKSlovakia
✓	✓	✓	✓	✓	✓	✓	✓	✓

Approved for use (✓) under EC 1107/2009 by Mutual Recognition of Authorisation and/or national regulations in the following EEA countries

ISIceland	NONorway
	✓

Additional information

Also used in

Australia, USA, Iran, Egypt, Morocco

Chemical structure

Isomerism

A chiral molecule. Difenoconazole has four stereoisomers [(2S,4S)-, (2S,4R)-, (2R,4R)-, and (2R,4S)-isomers] each having a different bioactivity. Technical substance has cis:trans ratio: 0.8-1.6

Chemical formula

C₁₉H₁₇Cl₂N₃O₃

Canonical SMILES

CC1COC(O1)(CN2C=NC=N2)C3=C(C=C(C=C3)OC4=CC=C(C=C4)Cl)Cl

Isomeric SMILES

International Chemical Identifier key (InChIKey)

BQYJATMQXGBDHF-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C19H17Cl2N3O3/c1-13-9-25-19(27-13,10-24-12-22-11-23-24)17-7-6-16(8-18(17)21)26-15-4-2-14(20)3-5-15/h2-8,11-13H,9-10H2,1H3

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
difenoconazole	Cis/trans isomer
difenoconazole	Unstated isomer
difenoconazole	-

General status

Pesticide type

Fungicide

Substance groups

Conazole fungicide

Minimum active substance purity

940 g kg⁻¹

Known relevant impurities

EU dossier: Toluene < 5g kg⁻¹

Substance origin

Synthetic

Mode of action

Systemic with preventative and curative action. Disrupts membrane function - inhibition of demethylation during ergosterol synthesis.

CAS RN

119446-68-3

EC number

601-613-1

CIPAC number

687

US EPA chemical code

128847

PubChem CID

86173

CLP index number

No data found

Molecular mass

406.26

PIN (Preferred Identification Name)

1-((2-((2E,4E)-2-chloro-4-(4-chlorophenoxy)phenyl)-4-methyl-1,3-dioxolan-2-yl)methyl)-1H-1,2,4-triazole

IUPAC name

3-chloro-4-((2RS,4RS;2RS,4SR)-4-methyl-2-(1H-1,2,4-triazol-1-ylmethyl)-1,3-dioxolan-2-yl)phenyl 4-chlorophenyl ether

CAS name

1-(2-(2-chloro-4-(4-chlorophenoxy)phenyl)-4-methyl-1,3-dioxolan-2-ylmethyl)-1H-1,2,4-triazole

Other status information

Relevant Environmental Water Quality Standards

Herbicide Resistance Class (HRAC MoA class)

Not applicable

Herbicide Resistance Class (WSSA MoA class)

Not applicable

Insecticide Resistance Class (IRAC MoA class)

Not applicable

Fungicide Resistance Class (FRAC MOA class)

Examples of recorded resistance

Physical state

White crystals

Formulations

Property

Value

Example manufacturers & suppliers of products using this active now or historically

Nufarm
Syngenta
BOC Sciences

Example products using this active

Amistar Top
Plover
Spyrale
Difcor 250 EC
Score EC
Dagonis
Carial star
Ascernity

Formulation and application details

Often supplied as an emulsifiable concentrate which is mixed with water and applied as a spray or as a flowable concentrate for seed treatments

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

Solubility - In water at 20 °C (mg l⁻¹)

15.0

Low

Solubility - In organic solvents at 20 °C (mg l⁻¹)

330000

Ethanol

610000

Acetone

500000

Toluene

3400

n-Hexane

Melting point (°C)

82.5

Boiling point (°C)

101

Degradation point (°C)

337

Flashpoint (°C)

285

Octanol-water partition coefficient at pH 7, 20 °C

2.29 X 10⁰⁴

Calculated

Log P

4.36

High

Fat solubility of residues

Solubility

Soluble

Data type

Regulatory data

Density (g ml⁻¹)

1.37

Dissociation constant pKa) at 25 °C

1.07

Strong acid

Vapour pressure at 20 °C (mPa)

3.33 X 10^-05

Low volatility

Henry's law constant at 25 °C (Pa m³ mol⁻¹)

9.0 X 10^-07

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

0.05

24 hr

Volatilisation is not considered critical for air pollution

From soil surface

9.0

24 hr

Volatilisation is not considered critical for air pollution

Maximum UV-vis absorption L mol⁻¹ cm⁻¹

Acid: 215nm = 29306, 235nm = 17556, 275nm = 1743
Neutral: 215nm = 28658, 235nm = 17392, 275nm = 1680
Alkaline: 220nm = 21210, 235nm = 17176, 275nm = 1542

Surface tension (mN m⁻¹)

62.8

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

133

Persistent

DT₅₀ (lab at 20 °C)

133

Persistent

DT₅₀ (field)

91.8

Moderately persistent

DT₉₀ (lab at 20 °C)

480

Very persistent

DT₉₀ (field)

305.4

DT₅₀ modelling endpoint

Note

EU dossier 2023: Lab studies DT₅₀ range 53-456 (normalised), DT₉₀ range 175->1000 days, Soils=14; field studies DT₅₀ range 20-265 days, DT₉₀ range 68-879 days; Other sources: DT₅₀ 49 days (DW4)

Dissipation rate RL₅₀ (days) on plant matrix

Value

8.1

Note

Published literature: RL₅₀ range 7.4-8.7 days, 2 field crops, n=2

Dissipation rate RL₅₀ (days) on and in plant matrix

Value

7.7

Note

Published literature RL₅₀ range 0.9-20 days,14 field & undercover grown crops, various matrices, n=23

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Stable

Note

Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7

Value

Stable

Note

Stable pH 5 to pH 9

Water-sediment DT₅₀ (days)

Stable

Water phase only DT₅₀ (days)

2.8

Moderately fast

Air degradation

As this parameter is not normally measured directly, a surrogate measure is used: ‘Photochemical oxidative DT₅₀’. Where data is available, this can be found in the Fate Indices section below.

Decay in stored produce DT₅₀

[Clementine; No observed residue decay after 32 days of cold storage; Field study]; [Pear homogenate: No observed residue decay @ <=20 DegC after 7 days; Lab study]

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d (mL g⁻¹)

K_oc (mL g⁻¹)

Notes and range

Freundlich

K_f (mL g⁻¹)

54.0

Slightly mobile

K_foc (mL g⁻¹)

3522

¹/_n

0.85

Notes and range

EU dossier 2023: K_f range 2.1-120.8, K_foc range 400-7730 mL g⁻¹, ¹/_n range 0.74-0.94, Soils=12

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

0.89

Calculated

Low leachability

SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate

Value

1.76 X 10^-02

Calculated

Note

Potential for particle bound transport index

High

Calculated

Potential for loss via drain flow

Slightly mobile

Calculated

Photochemical oxidative DT₅₀ (hrs) as indicator of long-range air transport risk

5.0

Calculated using the Atkinson method. Assumed 1.5E+06 OH/cm³, 12 hr

Below the level of concern for long-range air transport

Bio-concentration factor

BCF (l kg⁻¹)

330

Threshold for concern

CT₅₀ (days)

1.0

Known soil metabolites

Metabolite

Major/Minor fraction

$Click here for further information on Major/Minor fraction$

Estimated maximum occurrence fraction

Notes

1-(2-(2-chloro-4-(4-chloro-phenoxy)-phenyl)-2-1H-(1,2,4)triazol-yl)-ethanol (Ref: CGA 205375)

Minor fraction

0.097

1,2,4-triazole (Ref: CGA 71019)

Major fraction

0.23

Known groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

2-amino-3-[1,2,4] triazol-1-yl-propionic acid (Ref: CGA 131013)

triazole alanine; (TA)

Animal; Plant

[1,2,4]triazol-1-yl-acetic acid (Ref: CGA 142586)

triazole acetic acid; (TAA)

Animal

[1,2,4]triazol-1-yl-lactic acid (Ref: CGA 205369)

Triazole lactic acid; (TLA)

Animal

Phenobarbitone

Mouse (liver)

1-[2-chloro-4-(4-chloro-phenoxy)-phenyl]-2-[1,2,4]triazol-1-yl-ethanone (Ref: CGA 205374)
Note: Mice acute oral LD50 >5000 mg/kg bw,

difenoconazole-ketone

Plant

2-chloro-4-(4-chloro-phenoxy)-benzoic acid (Ref: CGA 189138)

difenoconazole-benzoic acid

Plant

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

1453

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Rat

High

(ppm diet)

Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)

> 189

Rat Reproductive NOAEL

Moderate

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2150

Anas platyrhynchos

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

> 5000 ppm

Anas platyrhynchos

Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)

9.71

Colinus virginianus NOEL

High

Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)

> 610

Eisenia foetida

Moderate

Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)

0.2

Eisenia foetida

Moderate

Soil micro-organisms

Nitrogen mineralisation: Unclear results
Carbon mineralisation: No significant adverse effect

Dose: 16.7 mg kg⁻¹ 28 Day

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

500

Folsomia candida

Non-target plants

> 10

Avena sativa Brassica napus Glycine maxima
Vegetative vigour, ER₅₀
as g ha⁻¹

> 10

Avena sativa Brassica napus Glycine maxima
Seedling emergence, ER₅₀
as g ha⁻¹

Honeybees (Apis spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

> 100

Apis mellifera

Low

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

> 177

Apis mellifera

Low

Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Chronic

Bumblebees (Bombus spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Mason bees (Osmia spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Other bee species (1)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Other bee species (2)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Beneficial insects (Ladybirds)

Beneficial insects (Lacewings) as Mortality LR₅₀ g ha⁻¹

> 200

Chrysoperla carnea Larva

Beneficial insects (Parasitic wasps) as Mortality LR₅₀ g ha⁻¹ 48 hr

178

Aphidius rhopalosiphi Adult

Beneficial insects (Predatory mites) as Mortality LR₅₀ g ha⁻¹ 7 day

112

Typhlodromus pyri

Beneficial insects (Ground beetles) as Mortality LR₅₀ g ha⁻¹

> 18.8

Poecilus cupreus

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

1.1

Oncorhynchus mykiss

Moderate

Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)

0.023

Oncorhynchus mykiss

Moderate

Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

> 1.05

Danio rerio Larva

Moderate

Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

0.77

Daphnia magna

Moderate

Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)

0.0056

Daphnia magna

High

Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)

0.15

Americamysis bahia

Moderate

Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)

0.77

Chironomus riparius 48 hr EC₅₀

Moderate

Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)

0.015

Chironomus riparius

Moderate

Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)

10.0

Chironomus riparius

Moderate

Aquatic plants - Acute 7 day EC₅₀, biomass (mg l⁻¹)

2.5

14 day NOEC

Moderate

Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)

0.032

Scenedesmus subspicatus

Moderate

Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)

0.87

Unknown species

Moderate

Mesocosm study data

NOEAEC mg l⁻¹

HUMAN HEALTH AND PROTECTION

General

Property

Value

Source; quality score; and other information

Interpretation

Threshold of Toxicological Concern (Cramer Class)

High (class III)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

1453

Rat

Moderate

Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)

2010

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 3.3

Rat 4 hr (nose only)

Other Mammal toxicity endpoints

ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)

0.01

Rat SF=100

ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)

0.16

Rat SF=100

AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)

AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)

0.16

Rat SF=100

Dermal penetration studies (%)

2-4

Dangerous Substances Directive 76/464

Exposure Routes

Public

No unacceptable risks to bystanders identified
Acceptable safety margin in place for consumers

Occupational

No unacceptable risks to workers identified

MRLs

European

EU MRL pesticide database

Great Britain

GB MRL Register

Notes

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

0.1

Mammalian dose elimination route and rate

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

Liver, heart, thyroid and kidney toxicant
US EPA - possible human carcinogen

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
IMDG Transport Hazard Class 9

CLP classification 2013

Health: H302, H318, H319, H332
Environment: H400, H410

WHO Classification

II (Moderately hazardous)

UN Number

UN3077

Waste disposal & packaging

Packaging Group III (minor danger)

Shelf-life, storage, stability and reactivity

Chemically stable under standard ambient conditions. Limited shelf-life

TRANSLATIONS

Language

Name

English

difenoconazole

French

difenoconazole

German

Difenoconazol

Danish

difenoconazol

Italian

difenoconazolo

Spanish

difenoconazol

Greek

Polish

difenokonazol

Swedish

difenokonazol

Hungarian

difenoconazole

Dutch

difenoconazool

Norwegian

difenokonazol

Record last updated:	21/08/2024
Contact:	aeru@herts.ac.uk
Please cite as:	Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242